Knee Brace with Expandable Members and Method of Using the Same

ABSTRACT

A knee brace has a body supporting first, second, and third expandable members. When expanded, the first, second, and third expandable members are positioned on the brace body to provide a counteracting force to the adduction moment of the knee.

PRIORITY

This application is a continuation of co-pending U.S. patent applicationSer. No. 12/668,673, entitled “Knee Brace with Expandable Members andMethod of Using the Same,” filed Jun. 3, 2010, assigned attorney docketnumber 3273/102, and naming David J. Hunter, Glenn Colaco, and DimitrijeStamenovic as inventors, the disclosure of which is incorporated herein,in its entirety, by reference.

U.S. patent application Ser. No. 12/668,673 is a National Phase filingof and claims priority to PCT application number PCT/US2008/070494,entitled “Knee Brace with Expandable Members and Method of Using theSame ,” filed Jul. 18, 2008, assigned attorney docket number 3273/102WO,and naming David J. Hunter, Glenn Colaco, and Dimitrije Stamenovic asinventors, the disclosure of which is incorporated herein, in itsentirety, by reference.

PCT application number PCT/US2008/070494, in turn, claims priority toU.S. provisional application Ser. No. 60/950,713, entitled “Knee Bracewith Expandable Members and Method of Using the Same ,” filed Jul. 19,2007, assigned attorney docket number 3273/101, and naming David J.Hunter, Glenn Colaco, and Dimitrije Stamenovic as inventors, thedisclosure of which is incorporated herein, in its entirety, byreference.

FIELD OF THE INVENTION

The invention generally relates to knee braces and, more particularly,the invention relates to knee braces constructed to provide acounteracting force to the adduction moment or abduction moment of theknee.

BACKGROUND OF THE INVENTION

Affecting an estimated thirty percent of adults over age 55, kneeosteoarthritis is one of the most frequent causes of lower limbdisabilities. Unfortunately, the incidence of knee osteoarthritis in theUnited States, Europe, and other regions is expected to rise aspopulations age.

Safe and effective treatments of this disease are limited. For example,a number of current therapeutic modalities focus primarily on reducingpain and improving joint function by means of non-specific, symptomaticagents, such as non-steroidal anti-inflammatory drugs (NSAIDs) and COX-2inhibitors. Undesirably, such agents are associated with high rates ofadverse events. Moreover, these drugs rarely completely relievesymptoms. Many individuals with knee osteoarthritis thus ultimatelyrequire a total knee replacement.

The symptoms of knee osteoarthritis often are described asmechanical—they occur with activity. Despite the above notedshortcomings of drug therapy, attempts to ameliorate the forces in theknee with braces have proven effective in relieving symptoms. Clinicallyeffective prior art braces, however, often are too bulky to comfortablywear for long periods, and difficult to wear underneath clothing.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the invention, a knee brace has abody supporting first, second, and third expandable members. Whenexpanded, the first, second, and third expandable members are positionedon the brace body to provide a counteracting force to the adductionmoment of the knee.

When in use, the first and third expandable members illustratively arepositioned to engage the interior part of the leg above and below theknee, while the second expandable member illustratively is positioned toengage the lateral part of the knee. Moreover, the brace also may have ahinge coupled with the second expandable member. Among other things, thehinge may have a stationary portion contacting the second expandablemember, and a pivoting portion having a gel material that contacts theknee (when in use).

In illustrative embodiments, the body has a main portion formed of aflexible material (e.g., neoprene) and at least one nylon strapsupporting one of the expandable members. Moreover, the first, second,and third expandable members each may include an inflatable bladder. Theexpandable members also may be fluidly connected and have a valve forcontrolling fluid flow (e.g., air) to each of them.

In accordance with another embodiment of the invention, a method ofstabilizing a knee first provides a knee brace having a body supportingfirst, second, and third expandable members, and then positions the kneebrace about the knee. Specifically, when positioned, the first and thirdexpandable members are positioned on the interior portion of the legabove and below the knee, while the second expandable member ispositioned on or very near to the lateral portion of the knee. Thefirst, second, and third expandable members cooperate in this manner toprovide a counteracting force to the adduction moment of the knee whenexpanded.

In accordance with additional embodiments of the present invention, aknee brace may also include a strap portion secured to a main portion.The main portion may be positionable over a subject's knee. The strapportion may have a plurality of expandable members (e.g., a first,second, and third expandable member) that provide a counteracting forceto an adduction moment of the knee. For example, the expandable membersmay be inflatable bladders and provide the counteracting force whenexpanded.

The counteracting force may include three individual forces applied tothe knee. For example, the first expandable member may apply a firstforce to the interior part of the leg above the knee. The secondexpandable member may apply a second force to the exterior part of theleg at the knee. Lastly, the third expandable member may apply a thirdforce to the interior part of the leg below the knee.

In accordance with still further embodiments, the knee brace may alsoinclude a hinge member located on the strap member. The hinge memberallows subject to bend the knee and may be coupled with the secondexpandable member. The hinge member may include a stationary portionthat contacts the second expandable member and a pivoting portion thatpivots within the stationary portion. The pivoting portion may alsoinclude a gel material that contacts the knee when in use.

In accordance with additional embodiments of the present invention, aknee brace may include a body portion, a first expandable member, asecond expandable member, and a third expandable member. Each of theexpandable members may be positioned on the body portion to provide aforce on the knee. For example, the first expandable member may apply afirst force to the medial part of the leg above the knee, the secondexpandable member may provide a second force to the lateral part of theleg at the knee, and the third expandable member may provide a thirdforce to the medial part of the leg below the knee. The first, second,and third forces may combine to counteract an adduction moment of theknee.

In accordance with further embodiments, the knee brace may also includea strap member secured to the body portion. The strap member may supportand mechanically connect the first, second, and third expandablemembers. The strap member may also have a non-elastic outer layer thatprevents the first, second, and third expandable members from ballooningoutwards.

In accordance with another embodiment of the present invention, a methodfor counteracting an adduction moment in the a knee can includepositioning a knee brace over a knee having an adduction moment, andinflating a first, second, and third expandable members on the kneebrace. In addition to the expandable members, the knee brace may alsohave a body portion. The inflated first, second, and third expandablemembers may each provide a force that, together, counteract theadduction moment of the knee. The expandable members may be inflated toa pressure that is dependent upon the user's level of activity.

BRIEF DESCRIPTION OF THE DRAWINGS

Those skilled in the art should more fully appreciate advantages ofvarious embodiments of the invention from the following “Description ofIllustrative Embodiments,” discussed with reference to the drawingssummarized immediately below.

FIG. 1A schematically shows a human leg with malaligned knee that can betreated in accordance with illustrative embodiments of the invention.

FIG. 1B schematically shows the skeletal structure of a human leg with avarus malaligned knee and the skeletal structure of a leg with a valgusmalaligned knee.

FIG. 2 schematically shows a generalized method of treating themalaligned knee shown in FIG. 1 by applying forces from inflatablemembers at the indicated sites.

FIG. 3 schematically shows a knee brace produced in accordance withillustrative embodiments of the invention.

FIG. 4 schematically shows additional use of the knee brace shown inFIG. 3, including additional details of the hinge member.

FIG. 5A schematically shows additional detail of the strap member andinflatable member, in accordance with illustrative embodiments of thepresent invention.

FIG. 5B schematically shows a cross-section and additional details ofthe hinge shown in FIG. 4, in accordance with embodiments of the presentinvention

FIGS. 6A and 6B schematically show higher stress areas of the knee braceshown in FIGS. 2-4.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In illustrative embodiments, a knee brace has a plurality of expandablemembers selectively positioned to provide a counteracting force to theadduction moment of a malaligned knee. To that end, the knee brace has abody supporting first, second, and third expandable members that applyforce to the leg in a manner that counteracts the adduction moment.Details of illustrative embodiments are discussed below.

FIGS. 1A and 1B schematically show human legs with malaligned knees thatcan be treated in accordance with illustrative embodiments of theinvention. As shown in FIG. 1A, the leg on the left (i.e., the person'sright leg) has a significant adduction moment, while the other legappears approximately normal/neutral. Specifically, any shift fromneutral or collinear alignment of the hip, knee, and ankle affects loaddistribution at the knee. The load-bearing axis is represented by a linedrawn from the center of the femoral head to the center of the ankle. Ina varus deformed knee (i.e., as shown in FIG. 1B), this line 120 passesmedial to the knee center 110 to create an adduction moment arm, whichincreases the force across the medial compartment 160. In a valgusdeformed knee, which is opposite to a varus deformed knee, theload-bearing axis 130 passes lateral to the knee center 110, and theresulting abduction moment arm increases the force across the lateralcompartment 170.

Perhaps one of the clearest ways to visualize the impact of theadduction and abduction moments is in relation to the spacing of theknee. In a typical, healthy knee, the spacing between the femur 140 andthe tibia 150 within the knee is primarily uniform. In other words, thespace/gap between the femur 140 and tibia 150 are substantially the samewithin the medical compartment 160 and the lateral compartment 170.However, when the knee is malaligned (e.g., varus or valgusmalalignment), the spacing may change and alter the load within theknee.

As shown in FIGS. 1B, when the knee suffers from a varus malalignment,the adduction moment reduces the space/gap between the femur 140 and thetibia 150 within the medial compartment 160 and increases thespacing/gap within the lateral compartment 170. Conversely, in a valgusmalaligned knee, the abduction moment decreases the space/gap within thelateral compartment 170 and increases the space/gap within the medialcompartment 160. The space/gap reduction in the respective compartments(e.g., the medial compartment 160 in the varus knee and the lateralcompartment 170 in the valgus knee) increases the load and forces withinthe compartments. The increased load and forces, in turn, cause thesymptoms described above (e.g., pain, loss of mobility, increased wearon the bones and cartilage, etc.). As described herein, variousembodiments of the present invention provide forces on the knee thatcounteract the adduction moment to return the spacing. Illustrativeembodiments, thus, counteract the load/forces within the medial andlateral compartments to a substantially normal level (e.g., increase thespacing/gap in the medial compartment 160 and reduce the spacing in thelateral compartment 170).

The normal range for alignment differs depending on the study. Forexample, in many studies, neutral (normal) alignment is 1 degree varus(range 0-2 degrees). With increasing osteoarthritis of the medialcompartment, the knee becomes increasingly varus (mean 3 degrees). Amongvarus knees, the mean±SD severity of varus was 3.13±1.25 degrees (range1.00-5.00 degrees), in K/L grade 0-1 knees, 3.04±1.95 degrees (range1.00-8.00 degrees), in grade 2 knees, and 4.34±2.6 degrees (range1.00-10.00 degrees), in grade 3 knees (P not significant for grade 0-1versus grade 2 knees; P=0.03 for grade 2 versus grade 3 knees).

Malalignment provides only a static impression of the mechanical forcesbeing imparted on the joint in one plane. To appropriately determinethese forces in more than one plane often requires 3-dimensionalkinematic analysis. During the stance phase of gait, the force acting atthe foot during gait passes medial to the center of the knee joint. Theperpendicular distance from the line of action of this force and thecenter of the knee joint is the lever arm of this force. This forcecombined with this lever arm produces a moment that adducts the kneejoint. This moment can be substantial and provide a major contributionto the total loading across the knee joint, which is usually labeled theadduction (or external varus) moment at the knee. The mean maximummagnitude of the adduction moment (M) during normal gait isapproximately 3.3 percent body weight (W) times height (h) and isgreater than either of the moments tending to flex or extend the knee.Studies of patients with medial knee osteoarthritis show that they have,on average, a higher M (4.2 percent W×h) than those withoutosteoarthritis.

Accordingly, illustrative embodiments create a force distribution aroundthe knee that counterbalances this difference in M (referred to as ΔM)between a knee with osteoarthritis and a normal knee, i.e., ΔM=0.9percent W×h. One study, for example, demonstrated the peak kneeadduction moment in persons with moderate to severe osteoarthritis was5.3 percent W×h (range 0.4-8.4 percent) versus those with mildosteoarthritis 3.5 percent (1.1-7.4 percent), with a p-value fordifference that was 0.06. In persons without osteoarthritis, Hurwitzpopulation would suggest the peak knee adduction moment is 3 percentW×h. This translates to a higher maximum reaction force on the medialcompartment by 25 percent over normal values in those with medial kneeosteoarthritis.

Illustrative embodiments of the invention counterbalance the adductionmoment by exerting forces on three strategic points along the leg. Tothat end, FIG. 2 schematically shows these forces, in which forces F1,which are exerted in an outward direction above and below the knee,substantially equal the force F2, which is exerted substantially at theknee and in an inward direction (i.e., in a direction that is oppositeto the forces F1). For example, the forces F1 illustratively act anequal distance d from the point of application of the force F2. Themoment produced by these forces that together counterbalance theabduction moment therefore equals the product of F1 and distance d.However, since illustrative embodiments of the knee brace are designedto counterbalance only the difference in that moment (also referred toas “delta M”, which is equal to 0.9 percent W×h), it follows that:

F ₁=0.9% W×h/d

To those ends, in accordance with illustrative embodiments, the forcesF1 and F2 are applied by means of a system of expandable members 14,such as inflatable latex bladders 330 (also identified by referencenumber “14”), over prescribed contact areas to which the forces F1 andF2 point, respectively, in the figures. FIGS. 3 and 4 schematically showa right leg knee brace having such members.

Specifically, as shown in those figures, the knee brace 300 has a body310 forming a plurality of straps 320 supporting the bladders 330 (onlyschematically shown), and a hinge 340 for facilitating movement. Inillustrative embodiments, the portion of the body 310 having no bladders330 is formed simply from a flexible material, such as neoprene. Theknee brace 300 may also have an opening 335 located on the anterior partof the brace 300. When the brace 300 is in use, the opening 335 may bepositioned over the knee cap to ensure proper positioning of the brace300.

As shown in FIG. 5A, the portions of the body 310 having the bladders330 producing force F1, however, have a more complex arrangement. Inparticular, those portions of the body 310 have a plurality of layersstarting with an inner, relatively soft, pliable material layer 510 thatremovably adheres to the skin. For example, this inner layer 510 may beformed from neoprene. The next adjacent layer includes the inflatablebladder, which should fixedly adhere to neoprene. Among other things,the inflatable bladder 330 may take the form of a latex balloon.Finally, the knee brace 300 has an exterior, relatively non-elasticmaterial layer 520 (e.g., nylon) that firmly resists outward expansionof the bladder. Consequently, rather than increasing the outer diameterof the brace 10, expansion of the bladder 330 at that point shouldsubstantially reduce the inner diameter of the brace 10.

The portion of the body 310 applying the inwardly directed force F2 hasan even more complex arrangement than the other portions describedabove. Specifically, this portion is configured to permit the leg tofreely pivot without compromising the structural integrity of thebladder. To that end, in addition to a soft pliable layer 510,inflatable bladder 330, and outer non-elastic layer 520, the knee brace300 may also include the above noted hinge 340 that extends through thesoft pliable layer 510 (e.g., the neoprene layer) and the non-elasticlayer 520 (e.g., the nylon layer). Generally, the hinge 340 may have amovable portion and a fixed portion (relative to the knee) radiallyinward of the movable portion. The movable portion may be connected withthe soft inner layer (or body portion 310), while the fixed portion maybe connected with the next succeeding layer; namely, the inflatablebladder 330. The strap member 320 or non-elastic material may helpresist outward expansion of the bladder 330.

As shown in FIGS. 4 and 5B, the hinge 340 may include a condylar pad360, protrusion 370, and coupling 350. The condylar pad 360 removeablyadheres the lateral portion of the knee at the location of F2 and may bemade from a soft silicon gel that has a consistency analogous to that ofa baby teething ring. Although the condylar pad 360 may rotate withrespect to the coupling 350, the condylar pad 360 should not rotaterelative to the knee (e.g., it should maintain contact and move with theknee).

Protruding from the lateral side of the condylar pad 360, the hinge 340has a protrusion 370 that engages with the coupling 350. The protrusion370 can be any number of structures including, but not limited to, anannular ring or a series of post members. As mentioned above, theprotrusion 370 engages with the coupling 350. To that end, the coupling350 can have a track 355, in which the protrusion 370 may sit. Toprevent disengagement, the protrusion 370 may have a thicker portion 375towards the end of the protrusion 370. In such embodiments, theprotrusion 370 may be “snapped” into the track 355 and the thickerportion 375 will prevent the protrusion 370 and, thus, the condylar pad360 from disengaging from the coupling 350. Once assembled, the condylarpad 360 and protrusion 370 can move relative to the coupling 350.

To facilitate the application of force F1 and attachment with theinflatable bladder 330, the hinge 340 can have arm member(s) 380 thatextend radially outward (e.g., above and below) from the hinge 340. Asshown in FIG. 5B, the inflatable bladder 330 can be located below thesearm member(s) 380. As the bladder 330 is inflated (e.g., to exert forceF1 on the knee), the arm member(s) 380 prevent the bladders 330 fromballooning out and ensure that the force is applied to the knee.

As one may expect, the presence of the inflatable bladders 330 under thearm member(s) 380 may tend to lift the condylar pad 360 off the kneewhen the bladders 330 are inflated. However, in illustrative embodimentsof the present invention, the body portion 310 and the strap members 320prevent this from happening. In particular, because the body portion 310and the strap members 320 are kept tight on the subject, the twocomponents are able to keep the condylar pad 360 in contact with theknee at all times. Additionally, as mentioned above, the body portion310 and the strap members 320 also help prevent the bladders 330 fromballooning out and help the knee brace 300 effectively apply the forceF2 to the knee.

As shown in FIG. 5B, the coupling 350 can be an annular ring having anopening 352. The opening 352 provides the user with access to theinflatable bladder 330 (e.g., to inflate the bladder(s) 330). Forexample, the knee brace may have a tube (not shown) extending from theinflatable bladder(s) 330 to the opening 325. The user may then inflatethe bladder(s) 330 in any of the manners described below (e.g., handpump, electric pump, blowing into a one-way valve, etc.).

As mentioned above, the inflatable bladder 330 may be located below thearm member(s) 380. In alternative embodiments, the inflatable bladder(s)330 may be located above the arm member(s) 380 (shown in dashed lines inFIG. 5B). In such embodiments, when inflated, the bladder(s) 380 willexert a force on the arm member(s) 380 that is directed towards theknee. The arm members 380 will, in turn, translate the force to thehinge 340 and condylar pad 360. In such embodiments, the hinge 340 andcondylar pad 360 apply the force F2 to the lateral portion of the kneeand there may be no direct contact between the inflatable bladder(s) 330and the skin.

It is important to note that the number and style of bladder(s) 330 usedat this location can vary. For example, some embodiments of the kneebrace 300 may only have a single annular bladder 330 that surrounds thehinge 340. Alternatively, the knee brace 300 may have one or more armmember(s) 380 (e.g., as described above) and a single bladder 330located above and/or below each of the arm member(s) 380. For example,if the hinge 340 has two arm members 380 (e.g., one extending up towardthe subject's hip and one extending down towards the subject's foot),the knee brace 300 can have an inflatable bladder 330 located aboveand/or below each of the two arm members 380. Alternatively, the hinge340 can have four arm members 380 extending radially out from the centerof the hinge 340 and the knee brace 300 can have a bladder 330 locatedabove and/or below each of the four arm members 380. Althoughillustrative embodiments of the hinge 340 are described above, it isimportant to note that other hinge mechanisms and orientations may beused and thus, the examples mentioned above are simply for discussionpurposes only.

Although the body 310 is described above as forming a plurality ofstraps 320 for supporting the bladders, other embodiments may havedifferent configurations. For example, the knee brace may have separatebody portions 310 and strap members 320 (e.g., the body 310 does notform the straps) that may or may not be secured to the body portion 310.In such embodiments, the body portion 310 may be made from an elasticmaterial, such as neoprene. This allows the knee brace to easily slideover and conform to the subject's knee and leg. Conversely, the strapmembers 320 may be made from a less elastic material, for example, nylonreinforced neoprene (e.g., neoprene with an outer layer of non-elasticnylon to prevent the bladders from ballooning out). The non-elasticnature of the outer layer 520 also allows the strap members 320 tomechanically connect the bladders 330.

In a manner similar to that described above, the strap members 320 maysupport the inflatable bladders 330. For example, as shown in FIG. 5A,the flexible layer 510 (e.g., the neoprene) may be located on the innerportion of the strap member 320 and may contact the knee or the bodyportion 310 of the brace 300. The non-elastic layer 520 (e.g., the nylonlayer) may be located on the outside of the strap member 320. Theinflatable bladder 330 may be located between the two layers. In thisconfiguration, the soft flexible layer 510 contacts the subject (or bodyportion 310) and allows the inflatable bladder 330 to expand towards theknee and apply the forces described above. The non-elastic layerprevents the bladders 330 from ballooning out. Additionally, asdescribed above, the strap member 320 may also include a layer orsection of soft silicon gel (e.g., at the hinge 340) that contacts andremovably adheres to the skin to provide additional comfort for theuser.

In still further embodiments, the strap members 320 may just simply be asingle layer of non-elastic material (e.g., similar to the outer nylonlayer 520) described above. In such embodiments, the strap members 320,the body portion 310, and the bladders 330 combine to form the threelayers described above. In particular, the body portion 310 acts as theinner elastic layer 510, the strap members 320 act as the outernon-elastic layer 520, and the bladders 330 may be located between them.

Although not shown, the knee brace 300 also has a channel for directingfluid flow into and out of the inflatable bladders 330. The forceapplied by the bladders 330 may be controlled by some additional means,such as a valve. Accordingly, a user may inflate the bladders 330 to anydesired pressure as required by their condition. In other words, theknee brace 300 is customizable to apply an appropriate pressure (e.g., 7psi) based upon the needs of the user. For example, a user engaging invigorous exercise may inflate the bladders 330 more than a user taking ashort walk. The user should be instructed, however, not to inflate thebladders 330 in a manner that would constrict blood flow. For example,it has been shown that pressures above 12 psi may cause discomfort andproblems with blood flow.

Conventional inflation mechanisms may be used to inflate the expandablebladders 330. For example, a simple hand pump or more complex electricpump may provide the air pressure. Alternatively, the valve may be asimple one way valve that permits a user to manually blow into thebladders 330. Additionally or alternatively, the bladders 330 may beself-inflating. Of course, other inflation mechanisms may be used andthus, the examples mentioned above are simply for discussion purposesonly. For example, a liquid may serve as the fluid within the bladders330.

In use, prior to performing a given activity, the user may simply slidethe knee brace over their knee. As mentioned above, the body 310 of theknee brace is made of flexible material such that the knee brace willslide over the user's knee/leg like a sock or sleeve. Once in position,the user may then inflate the bladders 330, which, when inflated, willprovide the forces (e.g., the two F1 forces and the F2 force) tocounteract the adduction moment within the knee. In some embodiments,the user may inflate the bladders 330 to different pressures dependingon the user's level of activity. For example, if the user is going for aleisurely walk, the user may inflate the bladders 330 to a relativelylow level/pressure. However, if the user is performing a more strenuousactivity (e.g., running, biking, playing a sport, etc.) the user mayinflate the bladders to a higher level/pressure to increase the forcesapplied to the knee.

In some embodiments, the portions of the body 310 having one or morebladders 330 effectively form straps 320. In other embodiments, theportions of the body 310 having the bladders 330 do not form straps 320,or some form straps 320 and others do not form straps 320. Moreover,some embodiments may have more than three bladders 330. For example,rather than use a single bladder 330, expandable members slightly aboveand below the knee may provide the force F2.

FIGS. 6A and 6B schematically shows the force points F1 and F2 of thebrace 300 with much of the rest of the body 310 removed (forillustrative purposes). Some embodiments of the brace 300 may have onlycorresponding portions, while others have the rest of the body 310(i.e., the part discussed above as having only a soft material).

It should be noted that discussion of specific materials and types ofdevices are not intended to limit various aspects of the invention. Forexample, devices other than latex bladders 330 may be used as expandablemembers, or the body 310 and/or strap members 320 may be formed fromdifferent materials having similar physical properties.

Illustrative embodiments of the knee brace 300 thus may be easilyadjustable to the needs of a specific individual. Moreover, this kneebrace 300 should be relatively easy to position on the leg. For example,as described above, the knee brace 300 may be simply slid over aperson's leg in a manner similar to sliding a sock over a person's foot.In addition, the hinge design should enable the knee to move through itsfull range of motion without significant resistance. Finally, this kneebrace 300 should be less bulky than conventionally effective designs,thus more readily permitting it to be worn under clothing.

Some alternative embodiments may be applicable to the opposite problem;namely, a valgus deformed knee. Accordingly, in such embodiments, thepositioning of the bladders 330 may be reversed to provide the force F2in an outward direction at the knee, and the forces F1 and an inwarddirection above and below the knee. In other words forces, in suchembodiments, the knee brace will provide forces F1 on the lateral partof the leg, above and below the knee and force F2 on the medial part ofthe leg at the knee.

Although the above discussion discloses various exemplary embodiments ofthe invention, it should be apparent that those skilled in the art canmake various modifications that will achieve some of the advantages ofthe invention without departing from the true scope of the invention.

What is claimed is:
 1. A knee brace comprising: a body supporting first,second, and third expandable members, the first, second, and thirdexpandable members being positioned on the body to provide acounteracting force to the adduction moment of the knee when theexpandable members are expanded.
 2. The knee brace as defined by claim 1wherein the first and third expandable members are positioned to engagethe interior part of the leg above and below the knee when in use, thesecond expandable member being positioned to engage the lateral part ofthe knee when in use.
 3. The knee brace as defined by claim 1 whereinthe body comprises at least one strap supporting one of the expandablemembers and comprising nylon.
 4. The knee brace as defined by claim 1wherein the first second and third expandable members each comprise aninflatable bladder.
 5. The knee brace as defined by claim 1 wherein thebody comprises a plurality of straps and a main portion comprisingneoprene.
 6. The knee brace as defined by claim 1 wherein the first,second, and third expandable members are fluidly connected, the kneebrace further comprising a valve for controlling fluid flow to theexpandable members.
 7. A method of stabilizing a knee, the methodcomprising: providing a knee brace having a body supporting first,second, and third expandable members; and positioning the knee braceabout the knee, positioning causing the first and third expandablemembers to be positioned on the interior portion of the leg above andbelow the knee, positioning also causing the second expandable member tobe positioned on the lateral portion of the knee, the first, second, andthird expandable members cooperating to provide a counteracting force tothe adduction moment of the knee when expanded.
 8. A knee bracecomprising: a main portion positionable over a subject's knee; a strapportion secured to the main portion and having a plurality of expandablemembers, the expandable members positioned to provide a counteractingforce to an adduction moment of the knee.
 9. A knee brace according toclaim 8, wherein the plurality of expandable members provides thecounteracting force when expanded.
 10. A knee brace according to claim8, wherein the plurality of expandable members includes a first, secondand third expandable member.
 11. A knee brace according to claim 10,wherein the counteracting force includes a first force applied by thefirst expandable member to the interior part of the leg above the knee,a second force applied by the second expandable member to the exteriorpart of the leg at the knee, and a third force applied by the thirdexpandable member to the interior part of the leg below the knee.
 12. Aknee brace according to claim 8, further comprising a hinge membercoupled with the second expandable member.
 13. A knee brace according toclaim 12, wherein the hinge member comprises a stationary portion and apivoting portion, the stationary portion contacting the secondexpandable member, the pivoting portion pivoting within the stationaryportion.
 14. A knee brace according to claim 13, the pivoting portioncomprising a gel material that contacts the knee when in use.
 15. A kneebrace according to claim 8, wherein the plurality of expandable memberseach comprise an inflatable bladder.
 16. A knee brace comprising: a bodyportion; a first expandable member positioned on the body portion toprovide a first force, the first force applied to the medial part of theleg above the knee; a second expandable member positioned on the bodyportion to provide a second force, the second force applied to thelateral part of the leg at the knee; a third expandable memberpositioned on the body portion to provide a third force, the third forceapplied to the medial part of the leg below the knee.
 17. A knee braceaccording to claim 16, wherein the first, second, and third forcescombine to counteract an adduction moment of the knee.
 18. A knee braceaccording to claim 16, wherein the first, second, and third expandablemembers provide the first, second, and third force when expanded.
 19. Aknee brace according to claim 16 further comprising a hinge memberlocated on the body portion, the hinge member allowing the subject tobend the knee.
 20. A knee brace according to claim 19, wherein the hingemember is coupled with the second expandable member.
 21. A knee braceaccording to claim 16, wherein the plurality of expandable members eachcomprise an inflatable bladder.
 22. A knee brace according to claim 16,further comprising a strap member secured to the body portion, the strapmember supporting the first, second, and third expandable members.
 23. Aknee brace according to claim 22, wherein the strap member mechanicallyconnects the first, second, and third expandable members.
 24. A methodof counteracting an adduction moment in a knee comprising: positioning aknee brace over a knee having an adduction moment, the knee brace havinga body portion and a first, second, and third expandable member;inflating the first, second, and third expandable members, the inflatedfirst, second, and third expandable members providing a first, second,and third force, the first, second, and third force counteracting theadduction moment of the knee.
 25. A method according to claim 24,wherein the knee brace further includes a hinge member located on thebody portion and coupled with the second expandable member, the hingemember allowing the subject to bend the knee.
 26. A method according toclaim 24, wherein the expandable members each comprise an inflatablebladder.
 27. A method according to claim 24, wherein the knee bracefurther includes strap member secured to the body portion, the strapmember supporting the first, second, and third expandable members.
 28. Aknee brace comprising: a body portion; a first expanding means forproviding a first force, the first expanding means positioned on thebody portion, the first force applied to the medial part of the legabove the knee; a second expanding means for providing a second force,the second expanding means positioned on the body portion, the secondforce applied to the lateral part of the leg at the knee; a thirdexpanding means for providing a third force, the third expanding meanspositioned on the body portion, the third force applied to the medialpart of the leg below the knee.
 29. A knee brace according to claim 28further comprising a hinge means for allowing the subject to bend theknee
 30. A knee brace according to claim 28, further comprising astrapping means for supporting the first, second, and third expandingmeans, the strapping means being secured to the body portion.
 31. A kneebrace according to claim 30, wherein the strapping means alsomechanically connects the first, second, and third expanding means.